January 6, 2012
Scientists Discover Key to Creating ‘Supersoldier’ Ants
According to a new report published in the journal Science, an international team of researchers has found a way to program ants to become so-called “supersoldiers”.
And what´s even more exciting, say researchers, the hidden switch for unlocking the trait in ants might also be present in a number of other species.All ant colonies, like those of their fellow Hymenoptera wasps and bees, are organized into various classes known as ℠castes´, which include, soldiers, workers and, of course, the queen.
The “trick” to creating the supersoldier ants, the research team detailed in their report, lies in manipulating environmental factors while the ant larvae are still developing.
While the supersoldier caste occurs naturally in some species of ants, the scientists were able to induce the creation of supersoldiers in two species that do not usually have them.
The study, led by Dr. Ehab Abouheif of McGill University in Montreal, detailed how providing the ant larvae with a particular hormone at a very specific time during their developmental process caused them to transform into massive-headed supersoldiers.
The research team examined a large genus of closely related ants known as Pheidole. Within the genus, only eight species are known to naturally produce the supersoldier caste. In these species, the supersoldier ants are tasked with the special job of defending the colony from potentially harmful invaders. This is done by using their comically over-sized heads to block the entrance the mound.
The researchers arrived at the idea that reprogramming might be possible after they observed that several non-supersoldier-producing species occasionally produced colony members with unusually large heads.
“We were collecting [ants] on Long Island, New York, and we noticed some monstrous-looking soldiers,” explained Dr Abouheif to BBC News reporter Victoria Gill.
Seemingly identical the supersoldier caste produced by their close cousins, Abouheif´s team first set out to investigate the cause behind the occasional appearance of the seeming mutants in other species.
Researchers already possess a considerable deal of knowledge regarding how the various casts develop within a colony. When the queen ant lays an egg, it possesses the genetic potential to develop into any of the various casts. It is therefore environmental factors alone, such as temperature and nutrition, which determine which caste it will later belong to.
And there is one environmental factor that is of particular significance in determining whether a colony member will be assigned to a job as worker, soldier or supersoldier, says Abouheif: a chemical inside the egg known to experts as ℠juvenile hormone´.
By treating any species with this biochemical at just the right stage of development, you can cause the larva to develop into a supersoldier, a fact that the study´s authors chalks up to the genus´ evolutionary heritage.
“The fact that you can induce it in all these different species, means that one common ancestor of all these species had [supersoldiers],” explained Dr. Abouheif to Gill.
The study stated that the researchers had “uncovered an ancestral development potential to produce a novel supersoldier subcaste that has been retained throughout a hyperdiverse ant genus that evolved 35 to 60 million years ago.”
Professor Nigel Franks of the University of Bristol, an expert in animal behavior and ecology, commented admiringly that the team´s research has revealed some of the "beautiful developmental biology that explains some fascinating evolutionary patterns.” Franks went on to call it “an absolutely marvelous piece of work.”
Yet the study doesn´t just elucidate a single interesting bio-evolutionary characteristic of one species. According to experts, the implications of the study can theoretically be extended to any number of plant and animal species.
“The question becomes, ℠Do all insects use a similar pathway as was found in the big-headed ants or is this something special to this group?´” wrote Corrie Moreau, an evolutionary biologist at the Field Museum in Chicago who has done extensive research in the field.
“Regardless, it suggests that we should look for evolutionary conserved pathways across the tree of life,” she added.
Dr. Abouheif hopes that his team´s discovery might have potentially useful implications for human society. For example, he thinks that scientists might one day be able to ℠unlock´ desired characteristics in organisms like plants in order to create higher nutritional value, or that it might be used to explore novel treatments for cancer.
“Who´s to say that all of that crazy growth that occurs in cancer isn´t the unleashing of some kind of ancestral potential,” he said.
“If we could find what that was, maybe we could reverse it.”
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